Russia has announced the capture of one of the main rebels in the Islamic insurgency in the south as it seeks to crack down on spiralling violence ahead of the 2014 Winter Olympics.

Ali Taziyev, known by his nom de guerre "Magas", has been detained by special operations forces from the FSB, Russia's security service. The FSB released video footage showing masked troops loading a bearded and dazed Taziyev into a helicopter. A website that acts as a mouthpiece for the rebels claimed he had been drugged. It said the arrest was a "serious loss to the mujahideen, but it would not alter the situation and stop the jihad".

The arrest has stunned observers of the conflict between Moscow and Islamic militants – from senior leaders to foot soldiers, rebels are nearly always killed in shoot-outs or raids. Analysts said the arrest could signal a new approach.

"They have realised that [killing] doesn't really stop insurgency," said Simon Saradzhyan, a security expert at Harvard University. "It's like a hydra. You cut off a few heads and new ones grow. Any killing in the north Caucasus, or any other closely knit society where vendetta exists, generates the desire to kill in revenge."

Taziyev was the military commander of the Caucasus Emirate, a far-reaching group born out of the separatist wars that ravaged Chechnya following the fall of the Soviet Union. Ultimately led by Chechen rebel Doku Umarov, it hopes to form an Islamic caliphate across Russia's southern, mainly Muslim, republics. After a six-year respite, during which it limited its attacks to the troubled south, in March the group claimed responsibility for a twin suicide attack on the Moscow metro that killed 40 people.

The increase in attacks could not have come at a worse time for Russia. The country is struggling to prepare for the 2014 Winter Olympics in Sochi, which is dangerously close to its troubled Caucasus region, just 250 miles from Grozny, the Chechen capital.

Earlier this month the chief of the FSB, Alexander Bortnikov, said intelligence officials were aware that rebels were planning to disrupt the Olympics. "Threats from al-Qaida were the reason for the cancellation of the Dakar 2008 road race," he told Russian news agencies, referring to the cancellation of the Paris-Dakar rally. "Militant leaders have clearly expressed their intention to play out a similar scenario on the eve of the 2014 Olympics."

He said rebels were continuing to seek to acquire nuclear, as well as biological and chemical, weapons. Chechen rebels forged ties with al-Qaida in the late 1990s and Russian leaders insist that they form the backbone of the movement.

The continued instability in the region poses the greatest challenge to the Kremlin's assertion that Vladimir Putin, the prime minister, has brought widespread stability to Russia.

Ahead of a visit to France this week, Putin told French media in Sochi that Russia would put in a "maximum effort" to ensure Olympic security. "The situation is restive, and has been for a long time in the north Caucasus," he said. "But, thank God, not in the Sochi region."

Cerwyn Moore, an expert at the University of Birmingham on the Caucasus insurgency, said Taziyev's capture "effectively decapitates the Ingush jamaat [rebel group] and severely weakens the insurgency".